The present invention relates to a cab for an agricultural vehicle having front and rear corners and two rear wheel fenders arranged one on each side at the rear of the cab.
U.S. Pat. No. 5,820,199 discloses a frame assembly for an operator""s compartment of a construction work machine, such as an earth moving machine. The compartment has an upper roof portion, a lower base portion and first and second side support assemblies connected between the roof portion and the base portion mid-way along the length of the compartment. Each side support assembly, includes a straight part, comprised of formed tube, and a curved part, formed of a fabricated box section having several individual wall plates.
In vehicle construction, the pillars supporting the roof are often referred to as A-pillars, B-pillars and C-pillars. A-pillars are arranged at the front comers of the cab to provide strength around the front windscreen, the B-pillars are the door pillars that strengthen the frame level with the position of the driver""s seat, and the C-pillars are arranged at the back of the cab and strengthen the frame of the cab around the rear window. Whereas U.S. Pat. No. 5,820,199 proposes a construction of the B-pillars that is curved to wrap around the wheel arches, in the present invention it is the C-pillars arranged at the back of the cab that are curved in this manner. Indeed, in the present invention, for a smaller cab, B-pillars are not required and the cab frame may have only A-pillars and C-pillars so that the lateral visibility is not impaired by support members.
The cab frame will normally include only two further support members disposed at the front comers of the cab and it is further preferred for these front support members and the upper portions of the rear support members to be curved to run inwards from the bottom to the top of the cab. This curving of the support members achieves improved cab strength and avoids the totally functional and utilitarian appearance of conventional cabs.
It is an object of the present invention to provide a cab for a vehicle, in particular a tractor, that is aesthetically pleasing and affords improved driver visibility.
According to the present invention, there is provided a cab for an agricultural vehicle having front and rear comers and two rear wheel fenders arranged one on each side at the rear of the cab, wherein the cab comprises a frame that includes two rear support members, the rear support members having lower portions disposed at the back of the cab between the two fenders and upper portions disposed above the fenders and offset laterally outwards from the lower portions.
Preferably, the upper portions of the rear support member are additionally offset to lie forwards of the lower portions at a distance from the rear of the cab. This allows the back window to be curved to wrap around the back of the cab and improves visibility still further. The moving of the upper portion of the C-pillar forwards has the effect of reducing the width of the doors and improves the rigidity of the cab.
It is convenient to form the rear support members from a tube that is bent, for example by hydroforming, to define a curved generally horizontal transition portion between the upper and lower portions. This is a more convenient and inexpensive manner of forming the curved support members than the assembled box sections described in the prior art reference discussed above.
Whereas in U.S. Pat. No. 5,820,199, the horizontal section of the side assembly simply wraps around the wheel arch or fender (in the prior art this is more likely to be a caterpillar track than a wheel), in the present invention, the horizontal transition section of the rear support member may additionally serve to support a window that is arranged at the rear of the cab to extend between the upper sections of the rear support members.
These and other objects, features and advantages are accomplished according to the instant invention by providing a cab for an agricultural vehicle having front and rear corners and two rear wheel fenders arranged one on each side at the rear of the cab. The cab comprises a frame that includes two rear support members. The rear support members having lower portions disposed at the back of the cab between the two fenders and upper portions disposed above the fenders and offset laterally outwards from the lower portions.